<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;

        }

        body {
            position: relative;
            display: flex;
            width: 100vw;
            min-height: 100vh;
            justify-content: center;
            align-items: center;
            overflow-x: hidden;
            padding: 50px;
        }

        .box {
            position: fixed;
            right: 5px;
            width: auto;
            height: auto;
            /* background-color:red; */
        }

        .box div {
            width: 50px;
            height: 50px;
            border-radius: 50%;
            background-color: red;
            margin-bottom: 5px;
            cursor: pointer;
        }

        .box div:first-child:hover {
            animation-name: abc;
            animation-duration: 0.3s;
            animation-fill-mode: both;
            ;
        }
        .mobile{
            
        }
        @keyframes abc {
            100% {
                transform-origin: 0% 50%;
                width: 150px;
                border-radius: 160px
            }
        }
    </style>
</head>

<body>
    <div class="box">
        <div class="mobile">13888888888</div>
        <div class="top"></div>
    </div>

</body>

</html>